docs(research): drop all fallow framing — codemap is structurally unique

User reframe: codemap is the only SQL-based code index in the market;
inspiration comes from the free and open internet (LSP spec, SQLite
docs, AST tooling), not code-by-code cloning of any peer tool. Drop
fallow as a yardstick throughout.

Vital information preserved (per "don't lose any vital information
that is used to execute the plan"):

- Closed-dead-subgraph motivator for C.9 — kept as an abstract pattern
  description in § 2.3 caveat (N-file packs with self-imports, non-
  zero fan-in, none reachable from real entry). Was previously cited
  to fallow.md § 0; now stands on its own merit.
- LSP read-side capabilities (show / impact / watch) — kept; LSP spec
  upstream is now the protocol authority instead of fallow's
  crates/lsp/.
- Runtime-tracing scope distinction — § 3 floor reframed to anchor on
  "different product class entirely" (live process data vs static
  analysis) instead of "fallow's paid moat."
- Predicate-as-API moat (A) — kept; justification now anchors on
  intrinsic merit (SQL is durable, agents compose any predicate)
  rather than "fallow ships verdicts; we don't."
- Schema-breadth moat (B) — kept; justification now "codemap-specific
  extractions; their richness directly determines what JOINs are
  expressible" rather than "fallow has none of these."

Section-by-section changes:

- HEADER — "Companion docs / Source for deep-dives" replaced with
  "Companion doc" (competitive-scan only) + "Positioning" paragraph
  declaring structural uniqueness.
- § 2.3 original-framing quote — paraphrased to drop the "(e.g.
  fallow, knip, jscpd)" parenthetical; pointers to roadmap.md for the
  full original wording. (roadmap.md itself still has the parenthetical;
  separate-PR scope.)
- § 2.3 caveat — closed-dead-subgraph case described abstractly; no
  source citation needed.
- § 2.5 LSP shim — "fallow has crates/lsp/" → "LSP spec upstream is
  the protocol authority."
- § 3 intro — mission framing rewritten; "equal/surpass fallow"
  language replaced with "extract maximum value from the SQL-index
  architecture; grow the ecosystem" + "only SQL-based code index in
  the market" positioning.
- § 3 Moat A — anchored on intrinsic merit (SQL durable + agent
  composability) instead of fallow comparison.
- § 3 Moat B — anchored on "substrate every recipe layers on; richness
  determines JOIN expressivity" instead of "fallow has none of these."
- § 3 ergonomic floors — dropped all "fallow is also fast" /
  "Convergent with fallow" annotations; reframed runtime-tracing as
  "different product class entirely (live process data, not static
  analysis)" + reframed telemetry-upload as standalone safety promise.
- § 4 — DELETED ENTIRELY ("What to inspect in the fallow source
  tree"). Replaced with "Inspiration sources for plan-PR authoring"
  table listing open specs / primitive sources only (LSP spec, SQLite
  docs, oxc node reference, Lightning CSS, JSON-RPC + MCP spec, TC39
  proposals, existing codemap surface, internal third-party graph
  audits). Discipline statement preserved: every plan PR cites the
  spec / primitive source it took inspiration from.
- § 5 (d) row + T-table T+5w → +7w cell — dropped fallow crates/lsp/
  refs; LSP spec is now the named authority.
- § 6 Q1 — dropped fallow.md § 6 citation; stale-index frequency now
  anchored on PR #46 + PR #56 internal evidence.
- § 6 Q4 — dropped fallow.md § 0 + § 6 citations; closed-dead-subgraph
  case cross-refs § 2.3 caveat instead.
- § 7 cross-references — removed research/fallow.md and fallow
  upstream entries. Added § 4 inspection list as a self-reference.
- § 8 errata § 2.3 row — dropped fallow.md citation; pattern described
  inline.

Net effect: the doc stands on codemap's intrinsic structural
properties. No peer-tool framing remains. The mission is now
self-coherent: extract max value from the SQL-index architecture +
grow the ecosystem, anchored on the unique-in-market positioning.

Author: SutuSebastian